From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp21.mail.ru (smtp21.mail.ru [94.100.179.250]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dev.tarantool.org (Postfix) with ESMTPS id 6A7C0401A40 for ; Thu, 24 Oct 2019 22:47:57 +0300 (MSK) References: <6d69f49ae7d4a58dfef92a654b0c6341df3f0344.1568152663.git.v.shpilevoy@tarantool.org> <20191024002155.6tn2b2zrju7wmi2n@tkn_work_nb> From: Vladislav Shpilevoy Message-ID: Date: Thu, 24 Oct 2019 21:53:17 +0200 MIME-Version: 1.0 In-Reply-To: <20191024002155.6tn2b2zrju7wmi2n@tkn_work_nb> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Tarantool-patches] [tarantool-patches] Re: [PATCH 1/1] app: exit gracefully when a main script throws an error List-Id: Tarantool development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alexander Turenko Cc: tarantool-patches@freelists.org, tarantool-patches@dev.tarantool.org Hi! On 24/10/2019 02:21, Alexander Turenko wrote: > I know, the patch was already pushed, but I looked on it briefly anyway. > If something is wrong, it may be fixed as a follow up. > It is LGTM, however I have one question: see below. > > WBR, Alexander Turenko. > >> @@ -678,6 +686,12 @@ tarantool_lua_run_script(char *path, bool interactive, >> ev_run(loop(), 0); >> /* The fiber running the startup script has ended. */ >> script_fiber = NULL; >> + /* >> + * Result can't be obtained via fiber_join - script fiber >> + * never dies if os.exit() was called. This is why diag >> + * is checked explicitly. >> + */ >> + return diag_is_empty(diag_get()) ? 0 : -1; > > This is the only part I'm a bit tentative: can the diagnostic area be > populated by a user somehow? I tried to do-- > > | fio.open('non_existent', {'O_RDONLY'}) > | os.exit() > > --in the main script and it seems that it uses some other diagnostic > area, because the fio error was not reported as the main script fail. Should it have been reported? Talking of why it is not now - well, yes, it uses another diagnostics area. tarantool_lua_run_script() starts a special fiber to run a script or a console. And the error is forwarded to the main fiber only when the script fiber does it voluntary, in the end of run_script_f(). In case of os.exit() the script fiber never finishes, and therefore never moves its diag to the main fiber. Os.exit() breaks event loop and freezes the current fiber. It makes ev_run() return in tarantool_lua_run_script(). After that we see that the diag is empty, because the script fiber never got to the point of filling it. > > So, things seems to work good, but I didn't got how exactly. >